from one bonfire to another--and when burnt out they are placed in the
fields as charms against blight.[13] The large ragwort--known in Ireland
as the "fairies' horse"--has long been sought for by witches when taking
their midnight journeys. Burns, in his "Address to the Deil," makes his
witches "skim the muirs and dizzy crags" on "rag-bred nags" with "wicked
speed." The same legendary belief prevails in Cornwall, in connection
with the Castle Peak, a high rock to the south of the Logan stone. Here,
writes Mr. Hunt,[14] "many a man, and woman too, now quietly sleeping in
the churchyard of St. Levan, would, had they the power, attest to have
seen the witches flying into the Castle Peak on moonlight nights,
mounted on the stems of the ragwort." Amongst other plants used for a
similar purpose were the bulrush and reed, in connection with-which may
be quoted the Irish tale of the rushes and cornstalks that "turn into
horses the moment you bestride them[15]." In Germany[16] witches were
said to use hay for transporting themselves through the air.

When engaged in their various occupations they often considered it
expedient to escape detection by assuming invisibility, and for this
object sought the assistance of certain plants, such as the
fern-seed[17]. In Sweden, hazel-nuts were supposed to have the power of
making invisible, and it may be remembered how in one of Andersen's
stories the elfin princess has the faculty of vanishing at will, by
putting a wand in her mouth.[18] But these were not the only plants
supposed to confer invisibility, for German folk-lore tells us how the
far-famed luck-flower was endowed with the same wonderful property; and
by the ancients the heliotrope was credited with a similar virtue, but
which Boccaccio, in his humorous tale of Calandrino in the "Decameron,"
applies to the so-called stone. "Heliotrope is a stone of such
extraordinary virtue that the bearer of it is effectually concealed from
the sight of all present."